3

I have an orange tree that has some issue but I can´t pin down what it could be, I don´t have that much experience with pinning down deficiencies or exceses on trees than in plants.

I will post some photos, the decoloration could be manganese or zinc (thats what I´ve found while researching on the internet) but what about the curled/clawed leaves? In plants clawed leaves normally is soil toxicity but for citrus trees people on the internet point at pests to be the issue, like thrips/miners, I don´t seem to see any pests on the leaves or under them.

Clawed leaves enter image description here enter image description here enter image description here

  • Can you show us the pot – Graham Chiu Feb 1 '18 at 16:54
  • Any chance that anyone in 100 M has used lawn herbcde ? – blacksmith37 Feb 1 '18 at 17:32
3

Trees planted in pots are much more constrained by the care that you provide them than trees planted in the earth as the latter have much greater access to symbiotic assistance from a larger variety of micro-organisms such as bacteria and mycorrhizal fungi. So, you need to make sure that the potting mix pH is close to optimal for your plant to thrive.

As @kevinsky correctly points out, the interveinal chlorosis seen in your pictures is diagnostic for manganese deficiency. This is likely to be functional rather than actual. Manganese is likely to be deficient in acidic soils, but your plant is presumably in a potting mix in a container of suitable size. But your pictures don't clearly show the pot size, and you have not provided a picture as requested.

Citrus trees prefer a pH of 6-7 but manganese is best absorbed at a pH range of 5-6.5

ph and nutrient availability

If you've only been watering with tap water with a pH of 8, you'll gradually alkalise the potting mix so that the plant develops a functional manganese deficiency. The long term solution is to repot into a citrus potting mix, but a short term fix is to apply a manganese foliar spray.

I tend to avoid watering my potted citrus trees with tap water because of this issue, and use water from my aquarium, or rain water which is usually slightly acidic.

Just for contrast, this shows the inverted V seen in functional Magnesium deficiency which does not occur at a pH of 8

magnesium inverted V

  • Actually that pH affect is not what a Dr of Ag explained to me. He said there is remarkable chemistry at the root hairs that can soluabilize almost anything in the soil like iron ( compounds). But adjusting the soil pH may help. He was studying soil trace element availability in the corn /soybean belt, may not apply to citrus. – blacksmith37 Feb 3 '18 at 19:46
  • I think that requires a decent microbial population hence my first sentence – Graham Chiu Feb 3 '18 at 20:17
  • Yes , I did not mean pH in not important but that there are also other factors. – blacksmith37 Feb 5 '18 at 15:36
  • Instead of decoloration, im more concerned about the curled leaves, isnt that like salinity problem? – Petar Petrov Feb 20 '18 at 8:46
2

This is a classic case of magnesium deficiency. Likely the soil ph has also made it difficult for the plant to use manganese as well. This fertilizer website has this picture below and it is also discussed in some detail here and a good description is from here

Manganese deficiency is indicated when leaves become mottled with lighter green or yellowish green areas between the major veins. The veins themselves and bands of tissue on each side remain green. Both young and mature leaves may show symptoms. Where the deficiency is mild the pattern gradually disappears as the leaves age, but if the deficiency is severe the pattern persists in mature leaves

manganese deficiency

This is most likely to be caused by an acid soil ph preventing the uptake of all the required minerals. Extremely acid or alkaline soils inhibit the uptake of minor nutrients. Your plant may also have or will in the future also show symptoms of iron and magnesium deficiency.

Fixing the problem:

  • repot the plant yearly with fresh soil less mix that has a balanced ph
  • use a fertilizer for citrus with chelated micro nutrients so they are more readily available
  • determine what the soil ph is and re-mediate. The most likely result is too acid which would be because of the ph of the tap water. Soft water is usually acidic. If too acid use lime, organic matter or mulches. Although much maligned clay top soil has excellent buffering properties for potted plants.
  • The first link where the photo comes from talks about magnesium instead of manganese. Tap water ph is alkaline, its arround 8 ph – Petar Petrov Feb 2 '18 at 11:44
  • @petar Petrov tap water ph varies widely due to many factors – kevinsky Feb 2 '18 at 16:50
  • What makes you say too acidic vs too basic? – Graham Chiu Feb 2 '18 at 19:26
  • Alkaline tap water implies that it contains Mg ( and Ca, etc.) . Cholorsis as shown in the leaves also results from iron and/ or N deficiency. But, I still think it is herbicide damage. – blacksmith37 Feb 2 '18 at 20:17
  • @blacksmith37 this pattern of chlorosis differs from iron or N deficiency. – Graham Chiu Feb 2 '18 at 20:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.